Field of the Invention
The present invention relates to a focus control apparatus that performs focus control of an interchangeable lens attached to a lens-interchangeable image capturing apparatus.
Description of the Related Art
Lens-interchangeable image capturing apparatuses such as digital cameras are each provided with a focus control apparatus that performs focus control (autofocus: AF) of an interchangeable lens attached thereto. Such image capturing apparatuses may be affected in an accuracy of the focus control, in other words, an in-focus accuracy by aberrations unique to the interchangeable lens.
Japanese Patent Laid-open No. 2004-347665 discloses an image capturing apparatus that detects an in-focus position by using a signal obtained by extracting a high frequency component of an object image and corrects the in-focus position depending on color information of the object image and on a chromatic aberration property of a focus lens, thereby achieving an improved in-focus accuracy. Japanese Patent Laid-open No. 2006-135513 discloses an image capturing apparatus that corrects a focus detection result by using a correction amount calculated from, for example, a spectrum intensity distribution of an object image and using information on focal points at respective wavelengths (in other words, on chromatic aberration) of an interchangeable lens, thereby achieving an improved in-focus accuracy.
These image capturing apparatuses disclosed in Japanese Patent Laid-open Nos. 2004-347665 and 2006-135513 can improve the in-focus accuracy by performing the correction relating to the chromatic aberration of the interchangeable lens, but cannot reflect an individual difference of the interchangeable lens from other lenses due to, for example, a manufacturing error onto its in-focus accuracy.